A cooler and dispenser for bottled water normally has a cooling reservoir within which the inverted neck of a water bottle is held. Water flows from the bottle until the water level closes the bottle neck, and a refrigerating system cools the reservoir and the water being held there. Water is dispensed by draining the reservoir, usually through a faucet, and when the water level clears the inverted bottle neck, air in the reservoir can enter the bottle, bubble to the top, and release more water to maintain the water level in the cooling reservoir.
In conventional devices of this kind, the air containing upper portion of the cooling reservoir is in open contact with the ambient air conditions surrounding the cooler, and it is that air which bubbles into the bottle as water is dispensed. This air can carry dust, bacteria and other contaminants. Moreover, leaving the upper portion of the cooling reservoir open permits the undesirable entry of dirt, insects, etc.
One approach to keep bottled water clear, although in a somewhat different type of cooler than that so far discussed, is shown in U.S. Pat. No. 3,333,741, issued Aug. 1, 1967, which discloses placing a plastic foam filter in the water bottle neck so that entering air is filtered through the foam. More recently, the owner of that patent commercially marketed an inverted bottle water cooler having a gasket in the open top of the cooling reservoir that seals against the inverted water bottle, thus closing the reservoir. Air is admitted to the cooling reservoir through foam filter portions of the gasket assembly. This arrangement limits the filtering effectiveness to that obtainable with relatively large foam blocks, and exposes the cooling reservoir to contaminants falling from the gasket-filter element assembly when that assembly is disturbed--as when changing filter elements.